package com.itHsuSE.demo2;

public class Work6 {
}

class Cale{
    public double num1;
    public double num2;
    public Cale(double num1,double num2){
        this.num1=num1;
        this.num2=num2;
    }
    public double jia(double num1,double num2){
        return num1+num2;
    }
    public double jian(double num1,double num2){
        return num1-num2;
    }
    public double cheng(double num1,double num2){
        return num1*num2;
    }
    public Double chu(double num1,double num2){
        if(num2==0){
            return null;
        }
        return num1/num2;
    }
}
